Elastomer compositions for use in a hydrocarbon resistant hose

ABSTRACT

A heat tolerant, pressure resistant elastomeric composition comprising a blend of a first ethylene-vinyl ester copolymer and a second copolymer selected from the group consisting of chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CPE), polychloroprene (CR), ethylene-acrylic elastomer (AEM), alkyl-acrylate copolymer (ACM), polyvinyl acetate (PVA), nitrile-butadiene rubber (NBR), hydrogenated nitrile-butadiene rubber (HNBR), and mixtures thereof; a hose manufactured therefrom; and a method for preparing the hose are described.

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/830,790, filed Apr. 21, 2004, which is acontinuation-in-part of U.S. patent application Ser. No. 10/663,324filed Sep. 15, 2003.

BACKGROUND OF THE INVENTION

The present invention relates generally to polymeric compositions. Moreparticularly, the present invention relates to polymeric compositionsuseful in the manufacture of automotive components, particularlyautomotive hoses for the transport of automotive fluids.

Hoses, particularly rubber hoses, are used in a variety of applicationsin the automotive industry as fuel feed hoses, torque converter hoses,power steering hoses and air conditioner hoses; as well as forindustrial and household utility applications such as hydraulic hoses,refrigeration hoses, washing machine hoses, propane gas feed hoses, highpressure air hoses, garden hoses, etc.

It is generally known that rubber surfaces do not always exhibit desiredresistance against chemical loads such as organic gases and solvents.Therefore, other approaches for improving the organic gas and solventresistance of rubber materials included using rubber materials whichhave a different polarity than the organic gas or solvent, increasingthe crosslinking of the rubber material, adding or increasing certainadditives, and increasing the wall thickness of the rubber tubematerial. All of these approaches have a down side. For example, the useof a rubber material having a polarity different from the organic gas orsolvent requires the use of more expensive rubber materials such aschloroprene rubber, acrylic rubber, epichlorohydrin rubber, and thelike; increasing the degree of crosslinking of the rubber used detractsfrom the softness and flexibility of the rubber; the addition ofadditives affects the processability and certain physical properties ofthe rubber; and increasing the wall thickness of the rubber materialalso increases the weight of the structure. Generally, these undesirableeffects overshadow any advantage gained in the improved gas and solventresistance.

In order to improve the impermeability of multilayered rubber hoses,typical approaches include the use of a metal film as a barrier layercoated on one of the inner layers. Such disclosures appear, for example,in U.S. Pat. No. 318,458 to Fletcher where there is disclosed amultilane tubular structure made from India rubber and having a tin foilliner. Other prior art patents such as U.S. Pat. Nos. 4,559,793 to Haneset al.; 4,759,455 to Campbell et al.; 5,182,147 to Davis; 5,271,977 toYoshikawa et al; 5,360,037 to Lindstrom; 5,398,729 to Spurgat; and5,476,121 to Yoshikawa et al. have attempted similar methods to reducethe permeability of fluids and/or gases through various tubes. Commonlyassigned U.S. Pat. No. 6,074,717 to Little et al.; and U.S. Pat. Nos.4,779,673 and 5,488,975 to Chiles et al. disclose metal coated syntheticrubber hoses used for circulation of fluids in radiant heating systemsin houses and in businesses and disclose the use of an inner nylontubular layer having a metal layer surrounding the nylon layer.

Polymeric material used to form the hose for accommodating fluids andgases under elevated pressures and/or high temperatures such as inautomotive air conditioner cooler hoses and power steering hoses mustmeet other critical requirements. For example, the polymeric materialmust exhibit low permeability to FREON or other coolant gases to preventsuch gases from escaping from the hose. Also such polymeric hose must beable to prevent outside moisture from entering the interior of the hosewhere it could contaminate the fluid or gas. In addition, the polymerichose must be capable of withstanding high heat and pressure, be able towithstand engine and impact vibration, and be capable of forminggas-tight connections.

In the case of hoses for accommodating coolant fluid for automotive airconditioners, etc., polymeric materials such as polychloroprene (CR),acrylonitrile-butadiene rubber (NBR), chlorosulfonated polyethylene(CSM), chlorinated polyethylene (CPE), polyacrylate (PA),ethylene-acrylic rubber (AEM), alkyl acrylate copolymer (ACM), polyvinylacetate, acrylonitrile-butadiene rubber (NBR), hydrogenatedacrylonitrile-butadiene rubber (HNBR), ethylene-propylene-dieneterpolymer (EPDM), cis-polybutadiene, cis-polyisoprene, polyurethane,polyamides such as nylon are often used as the material for forming thehose. For example, nylon 6 and nylon 66 are very low in coolant gaspermeability, but are relatively high in moisture permeability. On theother hand, nylon 11 and 12 are relatively low in moisture permeabilityand less susceptible to hydrolysis, but are moderately high in gaspermeability. Blends of any of the various nylons with other nylons,olefins or other materials are also used in such applications. Forexample, blends such as nylon 6, nylon 4, nylon 66, nylon 11, nylon 12,have been made to take advantage of desirable characteristics of one ormore of such nylons and, at the same time, reduce the effects of anyundesirable characteristics. However, blending the various polymericmaterials for the purpose of obtaining the desired benefits of eachindividual component actually acts to reduce the desired benefit becauseof the dilution effect of the other component(s) employed. Therefore,while one can obtain a variety of benefits by blending various polymers,the actual observed benefits may be reduced.

Ethylene-vinyl acetate copolymer (VAE) compositions are known. Forexample, U.S. U.S. Pat. Nos. 4,338,227 6,492,454; 5,942,580; 5,837,791;5,830,941; 5,807,948; 5,744,566; 5,698,651; 5,362,533; 5,135,988;4,338,227 and 4,309,332 describe various ethylene-vinyl acetatecopolymers and the uses thereof. Copolymers of ethylene and vinylacetate exhibit elastomeric characteristics and are commonly used toimprove adhesion properties of hot melt, solvent-based andpressure-sensitive adhesives. It is generally well known that the use ofethylene-vinyl acetate copolymers in the automotive industry andcommercial applications are mostly limited to coatings, adhesives,gaskets, O-rings and the like. For example, “Ultrathene”, a series ofethylene-vinyl acetate copolymers manufactured by Quantum Chemical, istypically used for adhesives, conversion coatings and thermoplasticmodifiers. Such EVA copolymers exhibit a wide range of melt indexes.Ethylene-vinyl acetate copolymers are also marketed by Bayer under thetrade name “Levapren”. These EVA copolymers are described as oil andheat resistant materials which may be used in air hose applications.U.S. Pat. No. 6,605,327 to Ramey et al. teaches the use of two separatelayers of an ethylene-vinyl copolymer in the manufacture of a multilayerhose.

Blends of vinyl esters with other polymers have been found to besomewhat effective in the manufacture of automotive hoses. For example,blends of ethylene-vinyl acetate with ethylene-vinyl acetate-carbonmonoxide terpolymers are useful in applications were flame retardant,low smoke, oil resistant flexible systems are desirable as coatings suchas coatings for wire and cable construction, are described in U.S. Pat.No. 6,133,367 to Arhart. However, there is no mention in the prior artof blends of a first vinyl ester with second copolymer selected from thegroup consisting of chlorosulfonated polyethylene (CSM), chlorinatedpolyethylene (CPE), polychloroprene (CR), acrylonitrile-butadiene rubber(NBR), polyacrylate (PA), ethylene-acrylic rubber (AEM), alkyl acrylatecopolymer (ACM), polyvinyl acetate, acrylonitrile-butadiene rubber(NBR), hydrogenated acrylonitrile-butadiene rubber (HNBR),ethylene-propylene-diene terpolymer (EPDM), cis-polybutadiene,cis-polyisoprene.

Ethylene-vinyl acetate copolymers and blends thereof have been employedin the wire and cable industry as a sheath or cover material surroundingelectrical wires. For example, polymeric blends of ethylene-vinylacetate copolymers with ethylene-vinyl acetate-carbon monoxideterpolymers which are particularly useful in applications where flameretardant, low smoke, oil resistant, flexible systems are desirable as awire coating. Patents disclosing the use of ethylene-vinyl acetatecopolymers as wire and cable coatings include U.S. Pat. No. 4,349,605 toBiggs et al.; U.S. Pat. No. 4,381,326 to Biggs et al; U.S. Pat. No.4,477,523 to Biggs et al.; U.S. Pat. No. 5,191,004 to Maringer et al.;U.S. Pat. No. 5,225,460 to Maringer et al.; and U.S. Pat. No. 5,226,489to Maringer et al. None of the references describe a self supportingtubular structure, nor is there any teaching of a blend of a first vinylester and a second copolymer selected from the group consisting ofpolychloroprene (CR), acrylonitrile-butadiene rubber (NBR),chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CPE),polyacrylate (PA), ethylene-acrylic rubber (AEM), alkyl acrylatecopolymer (ACM), polyvinyl acetate, hydrogenated acrylonitrile-butadienerubber (HNBR), ethylene-propylene-diene terpolymer (EPDM),cis-polybutadiene, cis-polyisoprene.

Choosing the right material or combination of materials to be used inthe construction of automotive hoses is becoming more and more difficultbecause the hoses are now required to withstand higher pressures andtemperatures than previous hoses performing the same tasks. Alsomandated regulations require that the hoses exhibit greaterimpermeability rates and resist stress over longer periods of time whilemaintaining manufacturing costs at an acceptable level. Therefore, themanufacturers of automotive hoses find it necessary to come up withnewer and better materials and combinations of materials to meet theserising needs. In order to achieve a material which meets regulations andstill retains the many desirable characteristics necessary to satisfythe manufacturer, attempts have been made to blend various materialswhich individually exhibit the desirable characteristics. However, it isgenerally found that, while these blended composite materials mayexhibit all of the desirable characteristics, these desirablecharacteristics have been drastically diluted to the point where thematerial is no longer acceptable.

Accordingly, in the manufacture of automotive components, particularlyhoses for use in the automotive industry, it would be desirable to finda material blended from two or more individual polymers, each of whichexhibits one or more desirable characteristics, wherein the individualcharacteristics in the resulting blend are not diluted by the otherpolymers.

SUMMARY OF THE INVENTION

It has now been found that blends of certain copolymers containing avinyl ester and at least one other polymer selected from the groupconsisting of ethylene-acrylic elastomer (AEM) or an alkyl-acrylatecopolymer (ACM) or mixtures thereof, exhibit unexpected properties thatare desirable in the manufacture of a variety of industrial andautomotive rubber components, such as automotive hoses, transmissionbelts, seals, dampers, engine mounts, particularly oil filled enginemounts, air duct housing, gaskets, CV joints boots, etc. For example,such blends exhibit high temperature and pressure resistance, improvedtensile strength, and improved hydrocarbon fluid resistance over eitherof the individual components alone. The particular copolymer blends ofthe present invention have been found to be particularly effective informing hoses useful in the transmission of various automotive fluidsand gases, e.g., engine oil cooler fluids, transmission oil coolerfluids, power steering fluids, radiator fluids, heater fluids, and thelike. For example, blends containing a first vinyl ester of a C₂ to C₆carboxylic acid, e.g., vinyl acetate, and a second polymer such as anethylene-acrylic elastomer (AEM) or an alkyl-acrylate copolymer (ACM) ormixtures thereof not only exhibit high temperature and pressureresistance, tensile strength, and improved hydrocarbon fluid resistance,but such blends appear to preserve the individual characteristics ofeach of the copolymer components of the blend.

Typically, ethylene-vinyl acetate copolymers are known to be heatresistant elastomers which are only fairly resistant to common fluidssuch as transmission fluids and power steering fluids. In order toimprove the oil resistance of an ethylene-vinyl acetate copolymermaterial, one approach would be to blend an oil resistant polymer withthe ethylene-vinyl acetate copolymer. Some of the more common oilresistant polymers would include chlorosulfonated polyethylene (CSM),chlorinated polyethylene (CPE), polychloroprene (CR), polyvinyl acetate(PVA), nitrile-butadiene rubber (NBR), hydrogenated nitrile-butadienerubber (HNBR), and the like. However, the blending of two ore more ofthese materials to obtain the beneficial characteristics of eachmaterial, more often than not, is only marginally successful, becausethe blending of the two materials simply dilutes their characteristicsin the blend as compared to the individual components alone. The dilutedcharacteristics of the blended material generally are most apparent whenthe material is aged.

It has now been discovered that blends of an ethylene-vinyl ester, e.g.,vinyl acetate, with certain other polymers, particularly,ethylene-acrylic elastomers (AEM) or alkyl-acrylate copolymer (ACM) ormixtures thereof, not only provide a material for use in the manufactureof hoses which meet government standards with regard to permeabilityrates, has good tensile strength, has good oil resistance, and has goodheat and pressure resistance, but such blends, unexpectedly, do not showthe typical effects of dilution. Such blends exhibit desirablecharacteristics which unexpectedly retain the desirable characteristicof the individual polymers when used alone. That is, the blend ofpolymers exhibits the beneficial properties of each polymer without theundesirable effects of dilution.

In one embodiment of the present invention, there is provided a heattolerant, pressure and hydrocarbon resistant composition, whichexhibits, improved hydrocarbon fluid impermeability. The heat tolerant,pressure and hydrocarbon resistant composition of the inventioncomprises a blend of a first copolymer and a second polymer wherein thefirst copolymer is different from the second polymer. The firstcopolymer comprises an ethylene-vinyl ester of a lower carboxylic acidand the second polymer is selected from the group consisting of ethyleneacrylic elastomer (AEM) and alkyl-acrylate copolymer (ACM) or mixturesthereof. Other polymeric materials may be employed in place of, or incombination with, the ethylene-acrylic elastomer or alkyl acrylatecopolymer; however, such other polymers when blended with ethylene-vinylacetate are only marginally effective Most notably, these other polymersinclude chlorosulfonated polyethylene (CSM), chlorinated polyethylene(CPE), polychloroprene (CR), ethylene-acrylic elastomer (AEM),alkyl-acrylate copolymer (ACM), polyvinyl acetate (PVA),nitrile-butadiene rubber (NBR), hydrogenated nitrile-butadiene rubber(HNBR), and the like.

In another embodiment of the present invention, there is provided a hoseespecially useful if the automotive industry to transport fuel, oil andvarious fluids. The hose of the present invention is manufactured from ablend of a first vinyl ester copolymer and a second copolymer selectedfrom the group consisting of ethylene-acrylic elastomer (AEM),alkyl-acrylate copolymer (ACM), and mixtures thereof. As indicatedabove, other polymers such as chlorosulfonated polyethylene (CSM),chlorinated polyethylene (CPE), polychloroprene (CR), polyvinyl acetate(PVA), nitrile-butadiene rubber (NBR), hydrogenated nitrile-butadienerubber (HNBR), and the like may be employed in addition to or in placeof the ethylene-acrylic elastomer or alkyl acrylate copolymer, but suchother polymers are only marginally effective. Most preferably, thepresent invention is directed to a blend of ethylene-vinyl ester, suchas vinyl acetate, and an ethylene acrylic elastomer or alkyl acrylatecopolymer. The automotive components formed from such ethylene-vinylester copolymers blended with an ethylene-acrylic elastomer, alkylacrylate, or mixture thereof, exhibits excellent oil resistance, fuelimpermeability, temperature and pressure resistance, and tensilestrength.

In still another embodiment of the present invention, there is provideda method for manufacturing the hose of the present invention whichcomprises providing a first vinyl ester copolymer, providing a secondcopolymer selected from the group consisting of chlorosulfonatedpolyethylene (CSM), chlorinated polyethylene (CPE), polychloroprene(CR), ethylene-acrylic elastomer (AEM), alkyl-acrylate copolymer (ACM),polyvinyl acetate (PVA), nitrile-butadiene rubber (NBR), hydrogenatednitrile-butadiene rubber (HNBR), and the like, preferably,ethylene-acrylic elastomer or alkyl acrylate copolymer, blending thefirst vinyl ester with the second copolymer, forming a hose from saidblend, and vulcanizing the hose.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with a first embodiment of the invention, a polymericcomposition comprises a blend of a first vinyl ester copolymer and asecond polymeric member. The first vinyl ester copolymer comprises avinyl ester of a C₂ to C₆ lower aliphatic carboxylic acid. Preferably,the vinyl ester copolymer is an ethylene-vinyl acetate copolymer whereinthe vinyl-acetate copolymer contains about 40 to 80 vinyl acetate.Vinyl-acetate copolymers commercially available from Bayer Corporationunder the name Levapren has been found to be particularly satisfactoryas the first vinyl ester copolymer of the blend used in manufacturingthe hose of the present invention. The vinyl ester copolymer is blendedwith a second polymer selected from the group consisting ofethylene-acrylic elastomer (AEM), alkyl-acrylate copolymer (ACM),chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CPE),polychloroprene (CR), polyvinyl acetate (PVA), nitrile-butadiene rubber(NBR), hydrogenated nitrile-butadiene rubber (HNBR), and the likepolyvinyl acetate (PVA), nitrile-butadiene rubber (NBR), hydrogenatednitrile-butadiene rubber (HNBR), and the like. In a preferred aspect ofthe invention, the second copolymer is an ethylene-acrylic elastomer(AEM) or an alkyl-acrylate copolymer (ACM). Most preferably, the secondcopolymer is an ethylene-acrylic elastomer available from E. I. DuPontunder the name Vamac.

Additional materials may also be employed as additives compounded intothe copolymer composition for the purpose of providing desiredcharacteristics of the composition. These additional materials include,for example, process aids; fillers; plasticizers; metal oxides orhydroxides; peroxides; coagents, and antioxidants. Other additives suchas vulcanization accelerators commonly used in polymeric compositionsfor use in preparing hoses may be added in appropriate amounts toprovide their desired effect.

Suitable processing aids includes stearic acid, stearates, polyethylene,amines, oils, organic esters, organic phosphate esters, mixed styrenatedphenylene diamine and the like.

Suitable fillers include materials, such as carbon black, silicondioxide, fumed silica, precipitated silica, diatomaceous earth,magnesium carbonate, magnesium silicate, aluminum silicate titaniumdioxide, talc, mica, aluminum sulfate, calcium sulfate, graphite,wollastonite, molybdenum disulfide, clay, calcium carbonate andcombinations thereof.

Suitable plasticizers include materials such as hydrocarbons, glycols,aldehydes, ethers, esters, ether-esters, and the like.

Suitable metal oxides and metal hydroxides include zinc oxide, zinchydroxide, magnesium oxide, magnesium hydroxide, calcium oxide, calciumhydroxide, aluminum hydroxide, and the like.

Suitable peroxides include 2,5-dimethyl-2.5-di(t-butylperoxy)hexyne-3;2,5-dimethyl-2,5-di(t-butylperoxy)hexane;a,a′-bis-(t-butylperoxy)-p-diisopropylbenzene, dicumyl peroxide,di-t-butyl peroxide; 1,1-bis(t-butylperoxy)-3,3,3-trimethylcyclohexane;2,4-dichlorobenzoyl peroxide; benzoyl peroxoide; p-chlorobenzoylperoxide; 4,4-bis(t-butylperoxy) valerate; t-butylcumyl peroxide;di-t-amyl peroxide; t-butyl hydroperoxide and combinations thereof.

Suitable coagents include N,N′, m-Phenylenedimaleimide (HVA2) and otherbismaleimides; triallyl cyanurate; tiallyl isocyanurate; diallylterephthalate; 1,2-vinyl polybutadienes; di- and tri-functionalmethacrylates and diacrylates; and metal ion versions of these coagents.

Suitable antioxidants include phenols, hydrocinnamates, diphenylamines,hydroquinone, hydroquinolines, mercaptobenzimidazoles, and the like.

Typically, the heat tolerant, pressure resistant elastomeric compositionof the present invention comprises a blend of a first ethylene-vinylester copolymer of a lower carboxylic acid and a second polymer selectedfrom the group consisting of ethylene-acrylic elastomer (AEM),alkyl-acrylate copolymer (ACM), and mixtures thereof. In certainapplication, other polymeric materials such as chlorosulfonatedpolyethylene (CSM), chlorinated polyethylene (CPE), polychloroprene(CR), polyvinyl acetate (PVA), nitrile-butadiene rubber (NBR),hydrogenated nitrile-butadiene rubber (HNBR), and mixtures thereof, mayalso be employed in place of or in combination with the blend ofethylene-vinyl ester and ethylene acrylate elastomer, alkyl acrylate, ormixtures thereof. Preferably, the composition comprises a blend of anethylene-vinyl acetate copolymer and an ethylene-acrylic elastomer or anethylene-alkyl copolymer, and most preferably, the composition comprisesa blend of ethylene-vinyl acetate and an ethylene-acrylic elastomer.

In accordance with a one embodiment of the invention, the compositioncomprises: about 10 to 75% by weight of a blend containing about 10 to90% by weight of an ethylene-vinyl acetate copolymer having about 40 to80% vinyl acetate, and about 90 to 10% of an ethylene-acrylic elastomer,an alkyl acrylate copolymer, or mixture thereof; and a plurality ofadditives in an amount of about 25 to 75% by weight, wherein theplurality of additives is selected from the group consisting of processaids; fillers; plasticizers; metal oxides or hydroxides; peroxides;coagents, and antioxidants.

Preferably, the composition of the present invention comprises:

about 10 to 50% by weight of a blend of an ethylene-vinyl ester with apolymer selected from the group consisting of ethylene-acrylicelastomer, alkyl acrylate, or mixtures thereof; and

about 0.8 to 2% by weight process aids based upon the total weight ofthe composition, wherein said process aids are selected from the groupconsisting of stearic acid, stearates, polyethylene, amines, oils,organic esters, organic phosphate esters and combinations thereof;

about 20 to 60% by weight fillers based upon the total weight of thecomposition, wherein said fillers are selected from the group consistingof carbon black, silicon dioxide, fumed silica, precipitated silica,diatomaceous earth, magnesium carbonate, magnesium silicate, aluminumsilicate titanium dioxide, talc, mica, aluminum sulfate, calciumsulfate, graphite, wollastonite, molybdenum disulfide, clay, calciumcarbonate and combinations thereof;

about 3 to 15% by weight plasticizers based upon the total weight of thecomposition, wherein said plasticizers are selected from the groupconsisting of hydrocarbons, glycols, aldehydes, ethers, esters,ether-esters and combinations thereof;

about 0 to 10% by weight metal oxides and/or hydroxides based upon thetotal weight of the composition, wherein said metal oxide and/orhydroxides are selected from the group consisting of zinc oxide, zinchydroxide, magnesium oxide, magnesium hydroxide, calcium oxide, calciumhydroxide, aluminum hydroxide and combinations thereof;

about 0.5 to 2% by weight peroxides based upon the total weight of thecomposition, wherein said peroxides are selected from the groupconsisting of 2,5-dimethyl-2,5-d(t-butylperoxy)hexyne-3;2,5-dimethyl-2,5-di(t-butyperoxy)hexane; dicumyl peroxide;a,a′-bis-(t-butylperoxy)-p-diisopropylbenzene; di-t-butyl peroxide;benzoyl peroxide; p-chlorobenzoyl peroxide; 4,4-bis(t-butylperoxiy)valerate; and combinations thereof;

about 0 to 5% by weight coagents based upon the total weight of thecomposition, wherein said coagents are selected from the groupconsisting of maleimides, triallyl cyanurate, triallyl isocyanurate,diallyl terephthalate, 1,2-vinyl polybutadiene, di- and tri-functionalmethacrylates, diacrylates, metal ion versions thereof and combinationsthereof; and

about 0 to 0.3% by weight antioxidants based upon the total weight ofthe composition, wherein said antioxidants are selected from the groupconsisting of phenols, hydrocinnamates, hydroquinones, hydroquinolines,diphenylamines, mercaptobenzimidazoles, and combinations thereof.

In accordance with a most preferred embodiment of the invention, thecomposition comprises:

about 10 to 50% by weight of a blend containing about 10 to 90% byweight vinyl acetate copolymer having about 40 to 80% by vinyl acetateand about 90 to 10% ethylene-acrylate elastomer;

about 0.2 to 0.7% by weight stearic acid;

about 23 to 38% by weight carbon black;

about 2 to 5% by weight silicon dioxide;

about 3 to 7% by weight trioctyl trimellitate;

about 0 to 7% by weight adipate type plasticizer;

about 0 to 8% by weight magnesium oxide;

about 0.1 to 0.75% by weight 1-octanedecanamine;

about 0.1 to 0.75% weight organic phosphate ester;

about 0.5 to 4% by weight organic peroxide;

about 0.25 to 1% by weight triallyl cyanurate;

about 0.25 to 1% by weight N,N′, n-phenylenedimaleimide;

about 0.25 to 2% by weight antioxidant selected from the groupconsisting of phenols, hydrocinnamates, diphenylamines, hydroquinones,hydroquinolines and mixtures thereof.

The composition of the invention is particularly advantageous in themanufacture of tubular structures for use in the automotive industry,for example, for transporting fuel and other automotive fluids such asthose fluids useful in engine oil coolers, transmission oil coolers,power transmission coolers, radiators, heaters, etc.

Hoses manufactured from the composition of the present invention notonly exhibit good heat tolerance, pressure resistance and hydrocarbonimpermeability, but such hoses unexpectedly retain such desired heattolerance, pressure resistance, and hydrocarbon impermeabilitycharacteristics at a surprising effective level over long periods oftime, even after aging.

In a third embodiment of the invention, a method for manufacturing heattolerant, pressure and hydrocarbon resistant automotive components, suchas automotive hoses having improved hydrocarbon fluid resistance isprovided. The method includes

providing an elastomeric composition comprising a first copolymer and asecond copolymer wherein said first copolymer is different from saidsecond copolymer, said first copolymer is an ethylene-vinyl ester of aC₂ to C₆ lower carboxylic acid and a said second polymer comprises acopolymer selected from the group consisting of ethylene-acrylicelastomer (AEM), alkyl-acrylate copolymer (ACM) or mixtures thereof.Other polymers may be employed in addition to or in place of the ofethylene-acrylic elastomer (AEM), alkyl-acrylate copolymer (ACM) ormixtures thereof. Such polymers include chlorosulfonated polyethylene(CSM), chlorinated polyethylene (CPE), polychloroprene (CR), polyvinylacetate (PVA), nitrile-butadiene rubber (NBR), hydrogenatednitrile-butadiene rubber (HNBR), and mixtures thereof; incorporatinginto said elastomeric composition, one or more additives selected fromthe group consisting of process aids, fillers, plasticizers, metaloxides, metal hydroxides, peroxides, coagents, antioxidants andcombinations thereof;

forming a hose of the blend containing the additives; and

vulcanizing the hose in an autoclave.

In a preferred method for manufacturing the tubular structure of theinvention, a continuous spiral production method is employed whichcomprises providing an inner layer of a material produced in amono-extrusion of an annular configuration.

A reinforcement material is generally employed in the manufacture of thehose to provide strength to the hose structure. The reinforcementmaterials include natural fibers such as cotton; synthetic fibers suchas polyester, nylon, rayon, aramid; and metal wire. The reinforcementmay be applied by knit or maypole type braid methods. Typically, thereinforcement material is applied to the annular extrudate in atwo-layer spiral format in which one layer is applied in a clockwisedirection and the other layer is applied in a counter-clockwisedirection.

An outer protective cover layer may be employed over the reinforcementlayer in a mono-extrusion of an annular configuration to provide toprotect the hose from the outer environment. The cover layer is aprotective layer of any of the commercially recognized materials forsuch use, e.g., elastomers, thermoplastic polymers, thermosettingpolymers and the like. Typically, the protective cover is a syntheticelastomer having good heat resistance, oil resistance, weatherresistance and flame resistance. Preferably, the outer protective coverlayer is a synthetic elastomer selected from the group consisting ofstyrene-butadiene rubber; butadiene-nitrile rubber such asbutadiene-acrylonitrile rubber; chlorinated rubber; chlorosulfonatedpolyethylene; vinylethylene-acrylic rubber; acrylic rubber;epichlorohydrin rubber such as Hydrin 200, a copolymer ofepichlorohydrin and ethylene oxide available from DuPont ECO;polychloroprene rubber; polyvinyl chloride; ethylene-propylenecopolymers; ethylene-propylene-diene terpolymers; ultra high molecularweight polyethylene; high density polyethylene; and blends thereof.

The hose of the invention is particularly useful in the transportationof air conditioner fluids, power steering fluids, transmission oilcooler fluids, etc. where the material forming the hose exhibits therequired heat tolerance, pressure resistance, impermeability resistanceto the fluid being transported through the hose, etc.

EXAMPLES Example 1

Parts per hundred of polymer (phr) Levapren ® 500 HV 100 80 90 90Hypalon ® 4085 (CSM) 10 10 Tyrin ® CM0136 (CPE) 10 10 Stearic Acid 1 1 11 Magnesium Oxide 10 10 10 10 N650 Carbon Black 75 75 75 75 SiliconDioxide 5 5 5 5 Trioctyl Trimellitate 10 10 10 10 1-Octadecanamine 1 1 11 Triallyl Cyanurate, 72% Dispersion 1 1 1 1 N,N′-m-PhenyleneDimaleimide 1 1 1 1 Dicumyl Peroxide; 60% Active 4 4 4 44,4′-Di(methylbenzyl)diphenylamine 2 2 2 2 Polyethylene 2 2 2 2Polyethylene Glycol 2 2 2 2 Cured 20 minutes @ 175° C. OriginalProperties Tensile Strength; psi 1699 2083 2059 1873 Elongation % 242195 213 243 100% Modulus; psi 785 1187 1074 923 Hardness; Shore A 77 7979 79 Compression Set, 70 h. @ 175° C. 48 73 58 51 After 336 hours @175° C. in Air Tensile Strength; psi 1497 1993 2514 2114 Elongation %136 1 14 24 100% Modulus; psi 1407 n/a n/a n/a Hardness; Shore A 54 4747 43 After 70 hours @ 175° C. in Chrysler MS9602 Automatic TransmissionFluid Tensile Strength; psi 1455 986 1153 1099 Elongation % 274 116 149175 100% Modulus; psi 446 813 670 480 Hardness; Shore A 54 47 47 43Volume Change; % 29 52 51 53Levapren is a trademark of Bayer CorporationHypalon is a trademark of DuPont Dow ElastomersTyrin is a trademark of DuPont Dow Elastomers

Example 2

Parts per hundred of polymer (phr) Levapren ® 600 HV 100 75 50 25 75 5025 Vamac ® PE 2166 25 50 75 100 Vamac ® DLS 25 50 75 100 Stearic Acid 11 1 1 1 1 1 1 1 Magnesium Oxide 10 10 10 10 10 10 10 10 10 N650 CarbonBlack 70 70 70 70 70 70 70 70 70 Silicon Dioxide 5 5 5 5 5 5 5 5 5Trioctyl Trimellitate 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 AdipatePlasticizer 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 1-Octadecanamine 1 1 1 11 1 1 1 1 Poly(oxy-1,2-ethanediyl),alpha- 1 1 1 1 1 1 1 1 1octadecyl-omega-hydroxy,-phosphate Triallyl Cyanurate, 72% Dispersion 11 1 1 1 1 1 1 1 N,N′-m-Phenylene Dimaleimide 1 1 1 1 1 1 1 1 1 DicumylPeroxide; 99% 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.44,4′-Di(methylbenzyl)diphenylamine 2 2 2 2 2 2 2 2 2 Cured 20 minutes @175° C. Original Properties Tensile Strength; psi 1806 1702 1486 13611054 1664 1482 1336 997 Elongation % 289 284 282 294 316 282 253 306 373100% Modulus; psi 761 691 662 632 527 670 643 583 381 Hardness; Shore A78 79 81 79 79 78 76 75 73 Compression Set, 70 h. @ 175° C. 49 62 67 7376 66 71 80 90 After 168 hours @ 150° C. in Air Tensile Strength; psi1645 1432 1200 1045 929 1588 1501 1421 1149 Elongation % 285 311 332 300336 293 240 271 336 100% Modulus; psi 925 863 782 689 689 924 905 954735 Hardness; Shore A 83 84 85 90 90 86 84 86 83 After 70 hours @ 175°C. in Air Tensile Strength; psi 1584 1477 1305 1186 1010 1587 1543 14931168 Elongation % 286 261 290 298 317 276 240 249 295 100% Modulus; psi1041 1048 954 918 803 1008 1039 1123 830 Hardness; Shore A 87 90 91 9192 88 88 88 90 After 336 hours @ 175° C. in Air Tensile Strength; psi1733 1844 1808 1531 1409 Not Tested Not Tested Not Tested Not TestedElongation % 93 117 118 136 155 100% Modulus; psi 1453 1372 1324 1115979 Hardness; Shore A 92 92 94 94 94 After 70 hours @ 162.8° C. inDexron ® III Automatic Transmission Fluid Tensile Strength; psi 14911419 1270 1220 989 1523 1502 1354 1124 Elongation % 280 252 283 273 318280 276 271 324 100% Modulus; psi 508 519 457 476 403 439 517 557 482Hardness; Shore A 54 54 58 58 63 63 59 66 74 Volume Change; % 34 28 2624 20 25 19 13 6 After 70 hours @ 150° C. in IRM 903 Oil TensileStrength; psi 1281 1266 1159 1065 852 1310 1255 1120 1015 Elongation %193 185 199 225 255 204 221 232 308 100% Modulus; psi 589 622 536 471377 541 463 439 322 Hardness; Shore A 44 49 49 50 51 44 46 50 55 VolumeChange; % 67 61 55 50 47 53 45 35 22Levapren is a trademark of Bayer CorporationVamac is a trademark of E. I. Dupont de Nemours and Company, Inc.Dexron is a trademark of General Motors Corporation

The percentages by weight of the various ingredients forming theautomotive components of the present invention are defined as weightpercent based upon the total weight of the elastomeric composition fromwhich the automotive component is derived.

The ratios of ethylene and vinyl ester in the ethylene-vinyl estercopolymers are defined as mol percent.

While preferred embodiments of the invention have been described indetail and exemplified in the above examples and specification, it willbe apparent to those skilled in the art that the invention may bemodified without deviating from the scope of the invention. Therefore,the foregoing examples and description are to be considered exemplaryrather than limiting and are not to be limited thereto.

1. A vulcanized, heat tolerant, pressure and hydrocarbon resistantelastomeric automotive component exhibiting improved hydrocarbon fluidimpermeability, wherein said automotive component comprises: about 10 to50% by weight of a blend comprising a first ethylene-vinyl estercopolymer and a second polymeric member selected from the groupconsisting of an ethylene-acrylic elastomer, an alkyl acrylatecopolymer, and mixtures thereof; and about 25 to 75% by weight of aplurality of additives selected from the group consisting of processaids, fillers, plasticizers, metal oxides, metal hydroxides, peroxides,coagents, antioxidants and combinations thereof.
 2. The automotivecomponent of claim 1, wherein said first ethylene-vinyl ester copolymeris an ethylene-vinyl acetate copolymer and said second polymeric memberis an ethylene-acrylic elastomer.
 3. The automotive component of claim2, wherein said ethylene-vinyl acetate copolymer contains about 40 to90% vinyl acetate.
 4. The automotive component of claim 2, wherein saidethylene-vinyl acetate copolymer contains about 50 to 80% vinyl acetate.5. The automotive component of claim 2, wherein said blend containsabout 10 to 90 weight percent ethylene-vinyl acetate copolymer and about90 to 10 weight percent ethylene-acrylic elastomer.
 6. The automotivecomponent of claim 1 further comprising 0 to about 75% by weight of anelastomeric polymer selected from the group consisting of chlorinatedpolyolefin, chlorosulfonated polyolefin, polychloroprene,ethylene-acrylic rubber, alkyl acrylate copolymer, polyvinyl acetate,acrylonitrile-butadiene rubber, hydrogenated acrylonitrile-butadienerubber, ethylene-propylene diene terpolymer, styrene-butadiene rubber,ethylene-propylene rubber, butyl rubber, cis-polybutadiene,cis-polyisoprene, polyurethane, polyamide and combinations thereof. 7.The automotive component of claim 1, wherein said one or more additivescomprises: about 0.1 to 8% by weight one or more processing aidsselected from the group consisting of stearic acid, stearates,1-octanedecanamine, polyethylene, amines, oils, organic esters, organicphosphate esters and combinations thereof; about 20 to 60% by weight oneor more fillers selected from the group consisting of carbon black,graphite, silicone dioxide, fumed silica, precipitated silica,diatomaceous earth, magnesium carbonate, calcium carbonate, magnesiumsilicate, aluminum silicate, titanium dioxide, talc, mica, aluminumsulfate, calcium sulfate, wollastonite, molybdenum disulfide, clay,calcium carbonate and combinations thereof; about 3 to 15% by weight oneor more plasticizers selected from the group consisting of hydrocarbons,glycols, aldehydes, ethers, esters, ether-ester, trioctyl trimellitateand combinations thereof; about 0.1 to 10% by weight one or more metaloxides and/or hydroxides selected from the group consisting of zincoxide, zinc hydroxide, magnesium oxide, magnesium hydroxide, calciumoxide, calcium hydroxide, aluminum hydroxide and combinations thereof;about 0.5 to 4% by weight one or more peroxides selected from the groupconsisting of 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3;2,5-dimethyl-2,5-di(t-butylperoxy)hexane;a,a′-bis-(t-butylperoxy)-p-diisopropylbenzene; dicumyl peroxide;di-t-butyl peroxide; 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane;2,4-dichlorobenzoyl peroxide; benzoyl peroxide; p-chlorobenzoylperoxide; 4,4-bis(t-butylperoxy) valerate; t-butylcumyl peroxide;di-t-amyl peroxide; t-butyl hydroperoxide and combinations thereof;about 0.1 to 5% by weight one or more coagents selected from the groupconsisting of maleimides, triallyl cyanurate, triallyl isocyanurate,diallyl terephthalate, 1,2-vinyl polybutadiene, di- and tri-functionalmethacrylates, diacrylates, metal ion versions thereof and combinationsthereof; and about 0.1 to 3% by weight one or more antioxidants selectedfrom the group consisting of phenols, hydrocinnamates, hydroquinones,hydroquinolines, diphenylamines, mercaptobenzimidazoles and combinationsthereof.
 8. The automotive component of claim 7, wherein saidcomposition comprises: about 10 to 90% by weight of an ethylene-vinylacetate copolymer, wherein said ethylene-vinyl acetate copolymercontains about 50 to 80% vinyl acetate; about 90 to 10% by weight of anethylene-acrylic elastomer; about 0.2 to 0.7% by weight stearic acid;about 23 to 38% by weight carbon black; about 2 to 5% by weight silicondioxide; about 3 to 7% by weight trioctyl trimellitates; about 0.1 to 7%by weight adipate type plasticizer; about 0.1 to 8% by weight magnesiumoxide; about 0.1 to 0.75% by weight 1-octanedecanamine; about 0.1 to0.75% by weight organic phosphate ester; about 0.5 to 4% by weightorganic peroxide; about 0.25 to 1% by weight triallyl cyanurate; about0.25 to 1% by weight N,N′, n-phenylenedimaleimide; about 0.25 to 2% byweight antioxidant selected from the group consisting of phenols,hydrocinnamates, diphenylamines, hydroquinones, hydroquinones,hydroquinolines and mixtures thereof.
 9. The automotive component ofclaim 1, wherein said automotive component is selected from the groupconsisting of automotive hoses, transmission belts, seals, dampers,engine mounts, air duct housing, gaskets and CV joint boots.
 10. Theautomotive component of claim 9, wherein said automotive component is ahose.
 11. A method for preparing a vulcanized, heat tolerant, pressureand hydrocarbon resistant automotive component having improvedhydrocarbon fluid impermeability, said method comprising: providing afirst ethylene- vinyl ester copolymer; wherein said vinyl ester is avinyl ester of a C₂ to C₆ lower carboxylic acid; providing a secondpolymeric material comprising a polymeric material selected from thegroup consisting of ethylene-acrylic elastomer (AEM), alkyl-acrylatecopolymer (ACM), ), and mixtures thereof; providing one or moreadditives selected from the group consisting of process aids, fillers,plasticizers, metal oxides, metal hydroxide, peroxides, coagents,antioxidants and combinations thereof; blending said firstethylene-vinyl ester copolymer, said second polymeric material, and saidone or more additives to form an elastomeric composition comprising saidfirst ethylene-vinyl ester copolymer, said second polymeric material,and said; one or more additives; forming said automotive component fromsaid elastomeric composition; and vulcanizing said automotive component.12. The method of claim 11, wherein said ethylene-vinyl ester isethylene-vinyl acetate and said second polymeric material is anethylene-acrylic elastomer.
 13. The method of claim 12, wherein saidethylene-vinyl acetate contains about 40 to 80% vinyl acetate.
 14. Themethod of claim 12, wherein said ethylene-vinyl acetate copolymercontains about 50 to 80% vinyl acetate.
 15. The method of claim 12,wherein said elastomeric composition comprises about 10 to 90% by weightsaid first ethylene-vinyl ester copolymer; about 90 to 10% secondpolymeric material, and about 25 to 75% by weight of one or moreadditives.
 16. The method of claim 11, further comprising about 0 toabout 75% by weight of an elastomeric polymer selected from the groupconsisting of chlorinated polyolefin, chlorosulfonated polyolefin,polychloroprene, polyvinyl acetate, acrylonitrile-butadiene rubber,hydrogenated acrylonitrile-butadiene rubber and combinations thereof.17. The method of claim 11 wherein one or more of said additivescomprises: about 0 to 8% by weight one or more processing aids selectedfrom the group consisting of stearic acid, stearates,1-octanedecanamine, polyethylene, amines, oils, organic esters, organicphosphate esters and combinations thereof; about 20 to 60% by weight oneor more fillers selected from the group consisting of carbon black,graphite, silicone dioxide, fumed silica, precipitated silica,diatomaceous earth, magnesium carbonate, calcium carbonate, magnesiumsilicate, aluminum silicate, titanium dioxide, talc, mica, aluminumsulfate, calcium sulfate, wollastonite, molybdenum disulfide, clay,calcium carbonate and combinations thereof; about 3 to 15% by weight oneor more plasticizers selected from the group consisting of hydrocarbons,glycols, aldehydes, ethers, esters, ether-ester, trioctyl trimellitateand combinations thereof; about 0 to 10% by weight one or more metaloxides and/or hydroxides selected from the group consisting of zincoxide, zinc hydroxide, magnesium oxide, magnesium hydroxide, calciumoxide, calcium hydroxide, aluminum hydroxide and combinations thereof;about 0.5 to 4% by weight one or more peroxides selected from the groupconsisting of 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3;2,5-dimethyl-2,5-di(t-butylperoxy)hexane;a,a′-bis-(t-butylperoxy)-p-diisopropylbenzene; dicumyl peroxide;di-t-butyl peroxide; 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane;2,4-dichlorobenzoyl peroxide; benzoyl peroxide; p-chlorobenzoylperoxide; 4,4-bis(t-butylperoxy) valerate; t-butylcumyl peroxide;di-t-amyl peroxide; t-butyl hydroperoxide and combinations thereof;about 0 to 5% by weight one or more coagents selected from the groupconsisting of maleimides, triallyl cyanurate, triallyl isocyanurate,diallyl terephthalate, 1,2-vinyl polybutadiene, di- and tri-functionalmethacrylates, diacrylates, metal ion versions thereof and combinationsthereof; and about 0 to 3% by weight one or more antioxidants selectedfrom the group consisting of phenols, hydrocinnamates, hydroquinones,hydroquinolines, diphenylamines, mercaptobenzimidazoles and combinationsthereof.
 18. The method of claim 17, wherein said composition comprises:about 10 to 90% by weight of an ethylene-vinyl acetate copolymercontaining about 50 to 80% vinyl acetate; about 90 to 10% by weight ofan ethylene-acrylic elastomer; about 0.2 to 0.7% by weight stearic acid;about 23 to 38% by weight carbon black; about 2 to 5% by weight silicondioxide; about 3 to 7% by weight trioctyl trimellitate; about 1 to 7% byweight adipate type plasticizer; about 1 to 8% by weight magnesiumoxide; about 0.1 to 0.75% 1-octanedecanamine; about 0.1 to 0.75% organicphosphate ester; about 0.5 to 4% by weight organic peroxide; about 0.25to 1% by weight triallyl cyanurate; about 0.25 to 1% by weight N,N′,n-phenylenedimaleimide; about 0.25 to 2% by weight antioxidant selectedfrom the group consisting of phenols, hydrocinnamates, diphenylamines,hydroquinones, hydroquinolines and mixtures thereof.
 19. The method ofclaim 11, wherein said automotive component is selected from the groupconsisting of hoses, belts, seals, dampers, engine mounts, and CV jointboots.
 20. The method of claim 19, wherein said automotive component ishoses, said method further comprising applying a reinforcing layercomprising natural or synthetic fibers selected from the groupconsisting of cotton, polyester, nylon, rayon, and aramid; or metalwire, said method further comprising applying a cover layer on an outersurface of said reinforcing layer, said cover layer comprising asynthetic elastomer selected from the group consisting ofstyrene-butadiene rubber, butadiene-acrylonitrile rubber, chloroprenerubber, chlorinated polyethylene, chlorosulfonated polyethylene,epichlorohydrin-ethylene oxide copolymer, polyvinyl chloride, and blendsthereof.
 21. In a vulcanized hose for conveying fluids in an automotiveengine cooler, transmission oil cooler, power transmission cooler,radiator or heater, the improvement which comprises employing as aninner tubular structure of the hose, a heat tolerant, pressure andhydrocarbon resistant composition exhibiting improved hydrocarbon fluidimpermeability compared to conventional hose-forming compositions,wherein said composition comprises: about 10 to 90% by weight of a nethylene-vinyl acetate copolymer containing about 50 to 80% vinylacetate; about 90 to 10% by weight of an ethylene-acrylic elastomer;about 0.2 to 0.7% by weight stearic acid; about 23 to 38% by weightcarbon black; about 2 to 5% by weight silicon dioxide; about 3 to 7% byweight trioctyl trimellitate; about 1 to 7% by weight adipate typeplasticizer; about 1 to 8% by weight magnesium oxide; about 0.1 to 0.75%by weight 1-octanedecanamine; about 0.1 to 0.75% by weight organicphosphate ester; about 0.5 to 4% by weight organic peroxide; about 0.25to 1% by weight triallyl cyanurate; about 0.25 to 1% by weight N,N′,n-phenylenedimaleimide; about 0.25 to 2% by weight antioxidant selectedfrom the group consisting of phenols, hydrocinnamates, diphenylamines,hydroquinones, hydroquinolines and mixtures thereof. said hose furtherincluding a reinforcing layer over said tubular structure, saidreinforcing layer comprising natural or synthetic fibers selected fromthe group consisting of cotton, polyester, nylon, rayon and aramid; ormetal wire, and a cover layer over said reinforcing layer, said coverlayer comprising a synthetic elastomeric selected from the groupconsisting of styrene-butadiene rubber, butadiene-acrylonitrile rubber,chloroprene rubber, chlorinated polyethylene, chlorosulfonatedpolyethylene, epichlorohydrin-ethylene oxide copolymer, polyvinylchloride, and blends thereof.